Toshiba GR200 Series Instruction Manual page 52

I = fault current
Zs = reach setting
Vso = offset reach setting
–IZso
Figure 2.1-6 Offset Mho characteristic on impedance plane
Figure 2.1-6 illustrates a voltage diagram in the offset Mho characteristic; the angle
comparison between the S1 and S2 phases are performed using Equations (2.1-19) and (2.1-20).
The offset Mho characteristic is obtained by dividing the voltage of Figure 2.1-6 by current I.
Element equations for reactance characteristic
(iii)
It is possible that the Mho characteristic operate with reactance characteristic; a level line or
a gradual descent line toward the R-axis is provided for the reactance characteristic. The
gradual descent one is set using variables Xs, θ1, and θ2, as shown in Figure 2.1-7.
Reactance element
X
Xs
o
a. Reactance element with a level line
The composite characteristic is available only when the load current flows from the local-
end to the remote-end. If the load current flows oppositely from the remote-end to the local-
end, the reactance characteristic will be a horizontal line, which is parallel to the R-axis. The
X
Offset Mho element
IZs
o
Mho element
R
Figure 2.1-7 Reactance characteristics
- 31 -
S1=V–IZs
V
R
S2=V+IZso
X
knee
Xs
θ1
o
b. Reactance element with a gradual descent line
6F2S1915 (0.46)
S2=Vp
V
θ2
R
GRZ200 (Soft 031 & 032)